Diffusion-Weighted Imaging with Sensitivity Encoding (SENSE) for Detecting Cranial Bone Marrow Metastases: Comparison with T1-Weighted Images

OBJECTIVE: This study was designed to determine whether diffusion-weighted imaging (DWI) with sensitivity encoding (SENSE) could detect bone marrow involvement in patients with cranial bone marrow (CBM) metastases. DWI results obtained were compared with T1-weighted imaging (T1WI) findings. MATERIALS AND METHODS: DWI with sensitivity encoding (SENSE; b value = 1,000) was performed consecutively in 13 patients with CBM metastases diagnosed pathologically and radiologically. CBM lesions were dichotomized according to the involved site, i.e., skull base or calvarium. Two radiologists qualitatively evaluated the relative conspicuousness of CBM lesions and image qualities in B0 and in isotropic DWI and in T1WI. According to region of interest analysis of normal and pathologic marrow for these three sequences, absolute signal difference percentages (SD%) were calculated to quantitatively analyze lesion contrast. RESULTS: All 20 lesions in 13 patients with CBM metastases revealed abnormal DWI signals in areas corresponding to T1WI abnormalities. Both skull base and calvarial lesions provided better lesion conspicuousness than T1WI and B0 images. Although the image quality of DWI was less satisfactory than that of T1WI, relatively good image qualities were obtained. Quantitatively, B0 images (SD%, 82.1+/-7.9%) showed better lesion contrast than isotropic DWI (SD%, 71.4+/-13.7%) and T1WI (SD%, 65.7+/-9.3%) images. CONCLUSION: For scan times of less than 30 seconds, DWI with SENSE was able to detect bone marrow involvement, and was superior to T1WI in terms of lesion conspicuity. DWI with SENSE may be helpful for the detection of cranial bone/bone marrow metastases when used in conjunction with conventional MR sequences.

MR Imaging of Medullary Streaks in Osteosclerosis: A Case Report

We present a case of medullary sclerosis of the appendicular skeleton in a patient with chronic renal insufficiency for whom MR imaging findings were char-acteristic. T1- and T2-weighted MR images showed multiple vertical lines (medullary streaks) of low signal intensity in the metaphyses and diaphyses of the distal femur and proximal tibia.

Age- Related Contrast Enhancement Study of Normal Bone Marrow in Lumbar Spinal MR Imaging

PURPOSE: The purpose of this study was to evaluate the degree of contrast enhancement of normal bone marrow in L-spine relating to aging and to determine the range of contrast enhancement in normal bone marrow. MATERIAL AND METHODS: We analyzed a total of 120 patients (20 per decade) who had undergone lumbar spinal MRI and who ranged in age from the 2nd decade to more than the 7th. Bone marrow revealed no abonormal pathology. Sagittal T1-weighted spin echo sequences were obtained before and after gadolinium administration. For each sequence, a region of interest was drawn within the L1 vertebral body from the midsagittal slice. Signal intensity (SI) values of each sequence were ascertained and the percentage increase in SI was calculated . RESULTS: After contrast enhancement, lumbar MRI revealed no statistically significant in the percentage increase in SI of normal bone marrow in relation to aging. Most patients (99 %) however showed an SI increase of between 10 % and 49 %. In only four, none of whom were aged over 40, was this increase above 50%. CONCLUSION: Lumbar MRI, revealed no statistically significant difference in percentage increase in SI in normal bone marrow relating to aging, but when the increase is above 50 % in a patient aged over 40, bone marrow pathology should be further investigated.

MR Imaging Findings of Bone Marrow Following Bone Marrow Transplantation

PURPOSE: To evaluate the features of magnetic resonance(MR) imaging of bone marrow (BM) following bone marrow transplantation (BMT). MATERIALS AND METHODS: Eighteen BMT recipients (8 severe aplastic anemia and 10 leukemia patients) underwent MR imaging. Fourteen were males and four were females, and their mean age was 27.2 years. Allogeneic transplantation was performed in 14 patients, unrelated transplantation in three, and peripheral blood stem cell transplantation in one. The mean interval between BMT and MR examination was 22.7 weeks. MR imaging was performed using a 0.5 T superconducting MR unit(Gyroscan T5, Phillips, Netherlands). Signal intensity(SI) on T1 weighted (T1WI) and short tau inversion recovery(STIR) images of lumbar vertebral BM, and on T1WI of pelvic BM, was analyzed with respect to that of muscle. RESULTS: In nine patients in whom BMT was successful, the SI of lumbar vertebral BM was low to slightly high on T1WI and iso to low on STIR images. Six patients with labile engraftment syndrome and two relapsed patients showed inhomogeneous high SI with scattered low signal areas on T1WI and variable SI on STIR images. In particular, in patients who had relapsed, the SI seen on STIR images was high. One patient in whom rejection had occurred showed homogeneous high SI on T1WI and low SI on STIR images of lumbar vertebral BM. The SI of pelvic BM, as seen on T1WI, was inhomogeneously high, irrespective of engraftment status. The SI of pelvic BM showed a larger high-signal portion than did lumbar vertebral BM seen on T1WI. CONSLUSION: MR imaging of lumbar vertebral BM was useful for the evaluation of BM status after BMT. Engraftment of the pelvis might be delayed compared to that of the lumbar vertebrae.

MR Imaging Findings of Bone Marrow Following Bone Marrow Transplantation

PURPOSE: To evaluate the features of magnetic resonance(MR) imaging of bone marrow (BM) following bone marrow transplantation (BMT). MATERIALS AND METHODS: Eighteen BMT recipients (8 severe aplastic anemia and 10 leukemia patients) underwent MR imaging. Fourteen were males and four were females, and their mean age was 27.2 years. Allogeneic transplantation was performed in 14 patients, unrelated transplantation in three, and peripheral blood stem cell transplantation in one. The mean interval between BMT and MR examination was 22.7 weeks. MR imaging was performed using a 0.5 T superconducting MR unit(Gyroscan T5, Phillips, Netherlands). Signal intensity(SI) on T1 weighted (T1WI) and short tau inversion recovery(STIR) images of lumbar vertebral BM, and on T1WI of pelvic BM, was analyzed with respect to that of muscle. RESULTS: In nine patients in whom BMT was successful, the SI of lumbar vertebral BM was low to slightly high on T1WI and iso to low on STIR images. Six patients with labile engraftment syndrome and two relapsed patients showed inhomogeneous high SI with scattered low signal areas on T1WI and variable SI on STIR images. In particular, in patients who had relapsed, the SI seen on STIR images was high. One patient in whom rejection had occurred showed homogeneous high SI on T1WI and low SI on STIR images of lumbar vertebral BM. The SI of pelvic BM, as seen on T1WI, was inhomogeneously high, irrespective of engraftment status. The SI of pelvic BM showed a larger high-signal portion than did lumbar vertebral BM seen on T1WI. CONSLUSION: MR imaging of lumbar vertebral BM was useful for the evaluation of BM status after BMT. Engraftment of the pelvis might be delayed compared to that of the lumbar vertebrae.

Evaluation of Severity in Aplastic Anemia by MR Imaging

PURPOSE: To evaluate the role of bone marrow (BM) magnetic resonance(MR) imaging for assessment of theseverity of aplastic anemia (AA). MATERIALS AND METHODS: Eighty patients with AA, ranging in age from 16 to 44years underwent MR imaging. Fifty four patients had clinically severe AA (SAA),while in 26 the condition wasmoderate(MAA). Sagittal T1-weighted images (T1WI) and short tau inversion recovery(STIR) images of lumbarvertebral BM were analysed. Bulk T1, T2 and rho values (msec) were also measured, with mixed sequences. Signalintensity (SI) on both T1WI and STIR was classified into four patterns according to the amount of fatty marrow :pattern I, homogeneous fatty marrow ; II, fatty marrow with focal cellular nodules ; III, mixed fatty and cellularmarrow ; IV, cellular marrow with focal fatty nodules. These SI patterns and bulk T1, T2 and rho values of thelumbar BM were compared with the clinical severity of AA. RESULTS: On both T1WI & STIR sequences, MR imaging oflumbar vertebral BM in patients with AA showed various SI patterns. Pattern I, II and III were much frequently seenin the SAA group (48 of 54 patients on T1WI and 43 of 54 on STIR) and pattern IV was common in the MAA group (16of 26 patients on T1WI and 18 of 26 on STIR). The SI patterns of AA seen on both T1WI and STIR sequences closelycorrelated with clinical severity (x2 test, p = 0.0001). Bulk T1 value was significantly different between SAA andMAA ( SAA : 382.82 msec +/- 113.91; MAA: 517.99 msec +/- 151.92 ; t test , p = 0.0001). CONCLUSION: The SI patternseen on MR imaging, and T1 relaxation time of lumbar spinal BM can be useful for assessing the severity of AA.

Radiologic Findings of Korean Gaucher Disease

PURPOSE: To document the radiologic characteristics of Korean Gaucher disease. MATERIALS AND METHODS: Fifteen bone marrow biopsy and laboratory data confirmed Gaucher disease patients (age 1 -21, mean 10.9 yr) wereundertaken plain X ray and MRI. Number of type I were 10, type II, 2, type III, 3. Seven were splenectomized oninitial evaluation or during follow up. Five enzyme treated patient were undertaken follow-up MR examinationduring 6 -40 month with 6 month interval. Conventional T1 and T2WI of spine and femur was performed and FMPSPGR inand out of phase image was also done. Volume of liver and spleen were measured, and bone marrow infiltration andpresence of infarction were scored according to 6 scale scoring system. Clinical data were also reviewed andcorrelated with the MR findings. RESULTS: Marrow infiltration was noted in 71.4% of all patients in MRI, while itwas in 45.7% with plain radiography. Type I group showed marrow infiltration in all but one cases, which wasparallel with ages, SGPT, and presence of osteopenia, reversely correlated with spleen size. Severe bonecomplications (infarction or fracture) were noted in 7 of 10 type I group, and 6 patients showed severe growthretardation (below 3rd percentile). Follow up MR examination of 5 patient showed decrease in liver and spleen sizefirst without bone change until 6 months. There showed bone regeneration in 2 patient 1 year after, and increasedfat signal in one patient 3.5 years after. In and out of phase images couldn't help in quantifying fatcomposition in bone marrow. CONCLUSION: Korean Gaucher patients revealed as more severe skeletal complicationsthan others reported from Western groups. MR examination is a effective modality to evaluate and monitor ofGaucher patients.

Peritumoral Bone Marrow Edema in Benign Giant Cell Tumor

PURPOSE: To evaluate the frequency of peritumoral bone marrow(BM) edema accompanying benign giant celltumor(GCT) of the appendicular bone by magnetic resonance(MR) imaging and to correlate MRI findings with those ofplain radiography and bone scintigraphy. MATERIALS AND METHODS: Eighteen cases of pathologically proven benignGCT of the appendicular bone were retrospectively analyzed using MR images, plain radiographs and bonescintigrams. A plain radiograph was available in 15 cases, and a scintigram in six. Marrow edema was defined asperitumoral signal changes which were of homogeneous intermediate or low signal intensity(SI) on T1WI and high SIon T2WI, relative to the SI of normal BM, and homogeneous enhancement on Gd-DTPA-enhanced T1WI. The transitionzone, sclerotic margin and aggressiveness of the lesion were assessed on the basis of plain radiographs. BM edemaseen on MR images was correlated with plain radiographic and scintigraphic findings. RESULTS: 1. Peritumoral BMedema was seen on MR images in 10 of 18 cases (55.5%). 2. In 8 of 15 cases for which plain radiographs wereavailable, MR imaging revealed BM edema. In six of these eight, transition zone was wide, while in two it wasnarrow. Six of seven patients without marrow edema showed a wide transition zone, and in one this was narrow.There was significant correlation between BM edema shown by MR imaging and the transition zone seen on plainradiographs (x2, p<0.05). But The aggressiveness shown by plain radiographs correlated only marginally, while thepresence of sclerotic rim did not correlate. 3. All six cases for which a bone scintigram was available showed anextended uptake pattern. In five of the six, MR imaging revealed edema. CONCLUSION: Peritumoral BM edema wasfrequently seen (55.5%) in the GCTs of appendicular bone ; it was more often shown in association with a widetransition zone by plain radiographs.

MR Features of Myelofibrosis: Correlation with Bone Marrow Biopsy Findings

PURPOSE: To characterize the magnetic resonance (MR) imaging features of myelofibrosis and compare them with bone marrow biopsy findings. MATERIALS AND METHODS: The authors retrospectively reviewed sagittal T1-and T2 weighted and short tau inversion recovery (STIR) images of the thoracolumbar spine of six patients (five males and one female, mean age 46) with biopsy-proven myelofibrosis. Marrow signal intensity of the thoracolumbar spine was classified with respect to those of muscle and fat, based on the consensus of two radiologists after visual inspection. These MR features were compared with the degree of fibrosis and marrow cellularity, as determined by bone marrow biopsy. RESULTS: In all patients, marrow signal intensity of the thoracolumbar spine was reduced onT1 and T2 weighted images (invariably low on T1 weighted images, low (2/6) to intermediate (4/6) on T2 weighted images). On STIR images, marrow signal intensity was variable (high (3/6) or low (3/6)), and this correlated with degree of fibrosis, not with marrow cellularity. The signal intensity of marrow with mild to moderate fibrosis was high on STIR images, while that of marrow with marked fibrosis was low. CONCLUSION: MR imaging features of myelofibrosis were characterized as low on T1 weighted images and low to intermediate on T2 weighted images. In addition, the signal intensity of STIR imaging correlated with degree of fibrosis.

MR Features of Myelofibrosis: Correlation with Bone Marrow Biopsy Findings

PURPOSE: To characterize the magnetic resonance (MR) imaging features of myelofibrosis and compare them with bone marrow biopsy findings. MATERIALS AND METHODS: The authors retrospectively reviewed sagittal T1-and T2 weighted and short tau inversion recovery (STIR) images of the thoracolumbar spine of six patients (five males and one female, mean age 46) with biopsy-proven myelofibrosis. Marrow signal intensity of the thoracolumbar spine was classified with respect to those of muscle and fat, based on the consensus of two radiologists after visual inspection. These MR features were compared with the degree of fibrosis and marrow cellularity, as determined by bone marrow biopsy. RESULTS: In all patients, marrow signal intensity of the thoracolumbar spine was reduced onT1 and T2 weighted images (invariably low on T1 weighted images, low (2/6) to intermediate (4/6) on T2 weighted images). On STIR images, marrow signal intensity was variable (high (3/6) or low (3/6)), and this correlated with degree of fibrosis, not with marrow cellularity. The signal intensity of marrow with mild to moderate fibrosis was high on STIR images, while that of marrow with marked fibrosis was low. CONCLUSION: MR imaging features of myelofibrosis were characterized as low on T1 weighted images and low to intermediate on T2 weighted images. In addition, the signal intensity of STIR imaging correlated with degree of fibrosis.

Marrow Pattern in the Proximal Femoral Metaphysis of Patients with Osteonecrosis of Femoral Head and Normal Subjects: Comparison on MR Images

PURPOSE: To predict early risk of osteonecrosis of the femoral head by comparison of the bone marrow pattern of the proximal femoral metaphysis(PFM) in normal subjects and patients with osteonecrosis of the femoral head on T1-weighted magnetic resonance (MR) images. MATERIALS AND METHODS: The authors retrospectively reviewed T1 (TR525/TE 25 msec) weighted coronal MR images of 67 hips with osteonecrosis and 65 normal hips in 39 patients with osteonecrosis of the femoral head and in 27 normal subjects. On the basis of bright signal intensity of fat, the proportion of remaining hematopoietic marrow in PFM was subdivided into 4 grades (0 to 3) by two radiologists. No evidence of remaining hematopoietic marrow was assigned grade 0, and grades 1, 2 and 3 represented scanty, moderate, and prominent hematopoietic marrow, respectively. Grades 0 and 1 were collectively defined as "predominantly fatty", grades 2 and 3 as "predominantly hematopoietic". The frequency of the predominantly fatty marrow in PFM was analyzed in relation to three age groups(<25,25-50,50<) and both sexes. RESULTS: The overall frequency of predominantly fatty marro in PFM was higher in hips with osteonecrosis than in normal hips (p<0.001). Especially in the male population under the age of 50, the frequency was apparently higher in hips with osteonecrosis, compared with normal hips (p<0.001). However, the male population aged over 50 or female population showed no statistically significant difference in our series. CONCLUSION: In proximal femoral metaphysis with osteonecrosis of the femoral head, fatty marrow conversion occurs apparently earlier than in normal subject. T1-weighted MR imaging could therefore be useful in predictiong early risk of osteonecrosis of the femoral head because of early fatty marrow conversion of the proximal femoral metaphysis.